Machine gun and automatic small arm of the gas operated type



Oct. 2, 1934;

. A. J. PALMER ET AL ,975,236

MACHINE GUN AND AUTOMATIC SMALL ARM OF THE GAS OPERATED TYPE Filed July6, 1935 dim (EH66 1 MM mnmu ZWAA Patented Oct. 2, 1934 UNITED STATESMACHINE GUN AND AUTOMATIC SMALL ARM OF THE GAS OPERATED TYPE ArthurJoseph Palmer and Percy Reuben Higson,

Westminster, England, assignors to Vickers- Armstrongs Limited,Westminster, England, a

British company Application July 6, 1933, Serial No. 679,156 In GreatBritain August 25, 1932 8 Claims.

This invention relates to machine guns and automatic small arms of thegas operated type. It has heretofore been customary to stop the forwardmovement of the gas operated piston rod by means of a stop memberinserted into or made integral with the gun casing, a shoulder on thepiston rod bearing against this stop member to limit the forwardmovement of the piston rod. This stop member has heretofore had a faceat 10; right angles to the direction of movement of the piston rod andthe shoulder on the piston rod has a similarly shaped face, and it isfound in practice that with such a construction the piston rod is liableto rebound with consequent disadvantages. The chief object of theinvention is to overcome this difficulty.

According to the invention the co-operating faces on the stop member andon the piston rod, instead of being at right angles to the direction ofmotion as mentioned above, are arranged at a suitable angle other than aright angle to the said direction of movement to produce a cushioningeffect so that rebound of the piston rod is prevented or substantiallyreduced.

In order that the said invention may be clear- 1y understood and readilycarried into effect, the same will now be described more fully withreference to the accompanying drawing in which:--

Figure 1 is a side elevation of part of a machine gun made in accordancewith the invention;

Figure 2 is a section on the line II-II in Figure 1, and

Figure 3 is a sectional view of the gun casing (omitting the piston rod)on the line III-III in Figure 1.

The gas operated piston rod A has at its upper part the abutment face Aand. the stop member B has the co-operating face B Each of the faces A Bis part of a frusto-conical surface and is in the example shown at anangle of sixty degrees to the longitudinal axis of the piston rod. Thefaces also slope in a rearward direction, i. e. the upper or outer edgesA (remote from the axis of the piston rod) are nearer to the rear end ofthe gun than the lower or inner edges. A stop arrangement as abovedescribed will limit the forward movement of the piston rod withoutappreciable rebound.

The faces A B may slope forwardly, instead of rearwardly as describedabove.

The stop member B is in the form of a rivet inserted in the gun casing Dand cut away to form the face B as shown in Figure 3.

The stop member B may however be formed integrally with the gun casingD.

E indicates the usual spring for pressing the piston rod forwardly.

What we claim and desire to secure by Letters Patent of the UnitedStates is:-

1. A machine gun or automatic small arm of D the gas operated typehaving a gas operated piston rod, an abutment on said piston rod, and arigid stop member for co-operating with said abutment, the co-operatingfaces of the abutment and stop member being at an angle other thanperpendicular to the direction of movement of the piston rod, forreducing rebound of the piston rod.

2. A machine gun or automatic small arm as in claim 1, wherein saidfaces are inclined with their outermost edges, remote from the axis ofthe piston rod, nearer to the rear end of the gun than their inneredges.

3. A machine gun or automatic small arm of the gas operated type havinga gas operated piston rod, anabutment on said piston rod, and a rigidstop member for co-operating with said abutment, the co-operating facesof the abutment and stop member being at an angle of sixty degrees tothe axis of the piston rod.

4. A machine gun or automatic small arm as in claim 1, wherein saidfaces are parts of frustoconical surfaces.

5. A machine gun or automatic small arm as in claim 1, wherein the stopmember is in the form of a rivet inserted in the gun casing and shapedto form an inclined stop face.

6. A machine gun or automatic small arm of the gas operated type havinga gas operated piston rod, an abutment on said piston rod, and a rigidstop member for co-operating with said abutment, the abutment and stopmember having co-operating faces at an angle other than perpendicular tothe direction of movement of the piston suitable for reducing rebound ofthe piston rod and the inclination being such that the outermost edgesof said faces are nearer to the rear end of the gun than their inneredges.

7. A machine gun or automatic small arm of the gas operated type havinga gas operated piston rod, an abutment on said piston rod, and a stopmember for operating with said abutment, the stop member being in theform of a rivet inserted in the gun casing and shaped between its endsto form a stop-face comprising part of a frusto-conical surface at anangle of sixty degrees to the axis of the piston rod with the outermostedge nearer to the rear end of the gun than its inner edge and theco-operating face of the abutment'being of similar shagpei and in-'clination.

8. A,machine gun or automatic small'arm fthegas operated type havinga-gas operated pie-Y ton red, a spring acting on said piston rod to movethe rod forwardly, an abutment on said piston red, and a rigid stopmember for co-operating with said-abutment to limit the extent ofmovement of said pistoii r'od under the action (if said spring; thecomparating. faces of the abut e 'ment and rigid. stop member being atan angle

